The present invention relates to a liquid sending and receiving joint device which is included in a liquid supply devise of, for example, a fuel cell or an ink jet printer, and which conducts liquid from a liquid reservoir to a liquid acceptor that accepts the liquid.
Devices using a liquid supply devise capable of freely attaching or detaching a liquid reservoir, which contains a liquid and from which the liquid flows out, and a liquid acceptor, which receives the liquid from the liquid reservoir, are currently widely used, for example, in ink jet printers, in lighters which use liquid fuels, and for administrating liquid drugs in medical treatments. Regarding the liquid supply devise, it is possible to directly replace the liquid reservoir itself when it becomes short of the liquid to supply. Accordingly, as compared to a method of directly supplying the liquid to a reserve tank or the like which is mounted in the main device, it is possible to easily supply the liquid with a high level of safety without soiling a user's hands too much. Particularly, when the supplied liquid that can affect the human body or can greatly deteriorate when exposed to the outside air is used, the above-mentioned liquid supply devise is very effective.
Moreover, recently the development of fuel cells which generate electric power by using liquids as a fuel has been pursued. Many electronic manufacturers are actively engaged particularly in the development of direct methanol fuel cells (DMFC) which use methanol as fuel. The DMFC is expected as a new type fuel cell for the next generation, which is to be used, for example, in laptops, in various kinds of portable electronic equipment, and in cell phones. However, in general, methanol has severe consequences on the human body. Inhaling methanol will damage the central nervous system and cause dizziness and diarrhea. Inhaling a large amount of methanol or allowing methanol to come into contact with the eyes will damage the optic nerve resulting in a high possibility of blindness. Consequently, methanol is highly dangerous and toxic. Therefore, for DMFC as well, in order for general consumers to supply the liquid fuel easily and safely, the means of supplying methanol without directly handling it, using the liquid reservoir as a cartridge is believed to be most appropriate, and development is conducted extensively for this purpose (Japanese Patent Laid-Open (Kokai) Publications Nos. 2003-308871, HEI 8-12301, and 2003-317756).
The above-described liquid supply devise needs to have a detachable liquid sending and receiving joint device for conducting the liquid from the liquid reservoir to the liquid acceptor. Examples of conventional joint devices include: Japanese Patent Laid-Open (Kokai) Publication No. HEI 10-789, Japanese Patent Laid-Open (Kokai) Publication No. HEI 8-50042, Japanese Patent (Kohyo) Publication No. 2003-528699, Japanese Patent Laid-Open (Kokai) Publication No. 2003-266739, Japanese Patent (Kohyo) Publication No. 2001-524896, Japanese Patent Laid-Open (Kokai) Publication No. 2000-289225, Japanese Patent Laid-Open (Kokai) Publication No. HEI 7-68780, Japanese Patent Laid-Open (Kokai) Publication No. HEI 5-254138, and Japanese Patent Laid-Open (Kokai) Publication No. 2003-331879.
However, any of the above-mentioned joint devices include many components and thereby have complicated structures. Therefore, miniaturization and cost reduction have limitations. Moreover, since they are structured to open a valve or the like when the pressure inside the liquid reservoir and the liquid acceptor increases, their structures tend to easily leak liquids. Therefore, a joint device which has a simplified coupling structure, which does not cause liquids to leak even under high internal pressure, and which can be smoothly attached or detached, has been strongly desired. Particularly for the DMFC which is supposed to be applied to portable electronic equipment, it is believed to require a joint devise which can be downsized from a normal size of recent portable electronic equipment to at least 103 mm3 or less. Moreover, in one of the above-cited examples, springs or the like are provided in flow paths where the liquid passes when the liquid reservoir engages with the liquid acceptor. While the joint devise is used, components such as metal ions from the springs elute into the liquid, thereby causing a problem of liquid contamination. In the case of the DMFC as well, the elution of metal ions is believed to affect the properties of the DMFC, such as deterioration of the catalysts, conductive materials, and electrolytes which are the constituent materials of the DMFC, as well as reducing the efficiency of the electrochemical reaction.